Remove duplicates from lists

[DavideViolante]

Examples:
Andrea, Juan, etc

only the most frequent should be considered.

related #79

[Micosilent]

After checking all the maps, there are duplicates in all the lists, according to my code gender-detection-from-name/duplicateDeletion, there are a few more duplicates than we might have originally thought.

There are 4082 duplicated names

• 3542 in the enMap
• 2561 in the itMap
• 3570 in the esMap

And if we exclude the esMap, then there are 2021 dupes between the itMap and the enMap ( of which 67 have different genders )

EDIT: I missed an actionable point, we could start by removing all the duplicates from the maps that have the same gender, and think about a solution to the differing genders further ahead.

PS: to verify yourself, checkout my branch, and run npm run name_lint